Personally I'm wary of running a large array of hard drives on some sort of server. Expensive, not green and subject to failures. I understand raid, etc, but it's about the cost and maintenance of all that vs $1 for a blank blu ray to carry 1 or maybe 2 tivo hd movies.

Of course there is the hassle of burning blu rays. I suppose if cost were no object and I didn't feel guilty about all that electricity I'd go with some enormous and costly raid solution.

Personally I'm wary of running a large array of hard drives on some sort of server. Expensive, not green and subject to failures. I understand raid, etc, but it's about the cost and maintenance of all that vs $1 for a blank blu ray to carry 1 or maybe 2 tivo hd movies.

Of course there is the hassle of burning blu rays. I suppose if cost were no object and I didn't feel guilty about all that electricity I'd go with some enormous and costly raid solution.

Any opinions?

You can get two HD movies on a BluRay disk? My numbers show about 5-6GB per hour for HD recorded on my Tivo and transferred to my computer. So if you say each movie is 2 hours that's less than 2TB for 100 movies. I'd go with the hard drive.

A 2TB without backup will cost about $120 (my original example was for a 1TB drive which also cost $120! I assumed .. wrongly .. that 2TB would cost more!).

But you gotta have backup, so make it 2TB/$240. Averaging 10gb per movie = 200 movies for $240. That's $1.40 for each movie, which is still more than $1 per blu ray. But a $1 blu ray is 25gb, so if you wanted to maximize you could fit 2 movies yielding $0.50/movie vs $1.40/movie. Though I probably wouldn't.

The thing is, I think the cost of blu ray media is one-time per movie. But the cost of a hard drive array is ongoing. You don't mind the expense and hassle of setting up a multi-hard drive array of some kind and keeping it running (ie, daily cost + drive replacements over time)? I guess I do, but I can be swayed .. that's why I'm asking for opinions. A good trade off for you, though, huh?

First mull: even though it cuts the hard drive array in half, a large array would still be required. And the rub is it costs a lot to keep adding drives .. because you need an expensive way to house all those drives .. or alternatively keep replacing drives with larger drives. Either way it's a pain.

Second mull: what's the advantage beyond saving hard drives? Once a movie is on blu ray, I can't see much need to also have it on a hard drive. Be great if I had a 100TB (10,000 movies!) hard drive to act as a quick access jukebox, but not there yet.

First mull: even though it cuts the hard drive array in half, a large array would still be required. And the rub is it costs a lot to keep adding drives

It costs a lot to keep adding BR disks.

Quote:

Originally Posted by markmarz

.. because you need an expensive way to house all those drives

Not so much. A 20 spindle array chassis can be had for under $1300.

Quote:

Originally Posted by markmarz

.. or alternatively keep replacing drives with larger drives. Either way it's a pain.

Not nearly the pain that dealing with thousands of BlueRay disks is. Plus, you can't play your BR on your TiVo.

Quote:

Originally Posted by markmarz

Second mull: what's the advantage beyond saving hard drives? Once a movie is on blu ray, I can't see much need to also have it on a hard drive.

I think you have that backwards. Once the movie is on the hard drive, there aren't a lot of reasons to put it on BRD.

Quote:

Originally Posted by markmarz

Be great if I had a 100TB (10,000 movies!)

A lot more than that. The average HD movie, recorded from CATV and recoded as h.264, runs about 6G. That works out to about 170 movies per Terabyte, or 17,000 movies in a 100T array.
hard drive to act as a quick access jukebox, but not there yet.[/QUOTE]

I was simply proposing a way of keeping the convenience of having them on hard drive while backing them up in a less expensive manner. If you weren't seriously considering creating a large enough array to maintain your entire video library, I don't understand the purpose of the original question.

Myself, I move stuff off to DVD periodically, including the metadata. Not terribly inconvenient. When I want to watch something that is on one of those DVDs, I simply put it in my PC's DVD drive and I can access it for download directly from my TiVo. No need to copy it back to the computer hard drive. I would never even consider creating a large disk array. The power consumption alone would be prohibitive (In my current financial state, that doesn't take much). Not to mention the additional heat.

I was simply proposing a way of keeping the convenience of having them on hard drive while backing them up in a less expensive manner. If you weren't seriously considering creating a large enough array to maintain your entire video library, I don't understand the purpose of the original question.

Myself, I move stuff off to DVD periodically, including the metadata. Not terribly inconvenient. When I want to watch something that is on one of those DVDs, I simply put it in my PC's DVD drive and I can access it for download directly from my TiVo. No need to copy it back to the computer hard drive. I would never even consider creating a large disk array. The power consumption alone would be prohibitive (In my current financial state, that doesn't take much). Not to mention the additional heat.

I am seriously considering the large array, don't get me wrong. It's just that I'm leaning more toward a blu ray solution and looking for other points of view. I appreciate your input & everyone's input very much!

Maybe it would help clarify my point of view by saying that currently I have a DataStor that makes 4 2tb drives look like a single 4tb drive in raid. It's nice and all, but it's just one step on a never ending procession of larger arrays as my capacity needs increase. Which they always do! And that can get mighty expensive. So I'm weighing continuing down that road or taking another approach. So far it still looks to me that blu rays are cheaper and convenient (I haven't found it difficult to store and access my dvds).

I currently have over 2500 dvds, most of them dvd-r recorded off tcm. They're great, considering they're standard def. Since most of the movies I watch are 1930's - 1960's, they're fine for their purpose, even on my 100" projector screen. But knowing my predilection for collecting, I can see I'll need a solution for high def program storage .. also off tcm mostly. That's the anticipated problem I'm looking to solve.

Not nearly the pain that dealing with thousands of BlueRay disks is. Plus, you can't play your BR on your TiVo.

I think you have that backwards. Once the movie is on the hard drive, there aren't a lot of reasons to put it on BRD.

A lot more than that. The average HD movie, recorded from CATV and recoded as h.264, runs about 6G. That works out to about 170 movies per Terabyte, or 17,000 movies in a 100T array.
hard drive to act as a quick access jukebox, but not there yet.

[/QUOTE]

Would you mind giving a rough estimate of the cost of your raid array? I'm thinking that even if it costs less once we're talking 5,000+ movies, the initial investment for that sort of capacity is large. Whereas the blu ray initial outlay is $200 for the burner & $1/blu ray. Net present value factors in with such a large difference in initial cost, I think. Plus the cost of blu ray per movie is paid once, not ongoing as with drive replacements, power consumption, etc.

Also I'm having trouble figuring out the $70 per spindle figure you mentioned in your other reply. What's the capacity per spindle?

Your comment on h.264 is interesting; that's quite a savings from 10gig to 6gig per movie; I'll have to look into that.

You have made a bad assumption. That being that bdr is more reliable than hard drives. It's not. The bee disks would also need backup. Also when media in a raid array fails, you know and recover. When optical media fails you don't until you try to use it. If you think your bdr discs are good enough without backup, then compare to simplex hard drive space, not redundant. Hard drive space is both cheaper and more reliable than BDR. Then there is the whole convenience and useability discussion.

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You have made a bad assumption. That being that bdr is more reliable than hard drives. It's not. The bee disks would also need backup. Also when media in a raid array fails, you know and recover. When optical media fails you don't until you try to use it. If you think your bdr discs are good enough without backup, then compare to simplex hard drive space, not redundant. Hard drive space is both cheaper and more reliable than BDR. Then there is the whole convenience and useability discussion.

Interesting. I think blu rays are at least touted as more reliable than dvd-r, yet I haven't had a problem reading any of my dvd-rs, including those over 10 years old. But of course you're right, a well maintained hard drive array with backup is always going to serve up the same bits reliably. It's just the cost I'm considering. I wouldn't consider backing up either my dvds or blu rays; the cost & hassle isn't worth it. Not like the data is priceless.

OTOH when a hard drive fails everything on it is gone. The drive has to be replaced, and then reloaded from the backup. When a blu ray is unreadable the content is gone forever, but it's just 1 movie (or two). I don't think it's likely that all or even a large percentage of blu ray media will become unreadable 10 years from now or even longer. But of course that's just my opinion; time hasn't passed yet.

You should do some research on writeable media logevity. You have a commonly held belief that just because you have not personally had a failure that you will not. These were not made for long-term archival storage, and unless they are junk, do not give outward signs of failure until the data starts to disappear. Hopefully you will not be surprised by going through and testing some of your older media, but you may be.

BTW, With 4 2TB drives, you could run RAID-5 and have 6GB of storage instead of just mirroring to get 4TB. It would be slower, but for the purposes of backing up and serving movies, it's fast enough. Personally I don't put all my eggs in one box anymore, though... I have one computer with a 2TB drive that holds all the movies I've bothered to store and serves them, and it automatically mirrors across the network to another computer that has a 1.5TB (usable space) RAID5 array. Both computers run pytivo and can serve up movies in the event of any one failure.

I'm not worried about the power consumption of having all this on rotational storage since I would have both of those computers running for other reasons anyway. If anything happens to either machine, I can still have full access to everything until I can replace the bad hardware. The whole thing is way less effort than burning anything to optical media. It's so little effort that adding the step of transcoding to H.264 and possibly losing some quality just isn't worth it for me, although it might make it faster for when I want to take a something to-go on my laptop or phone.

Just some more food for thought.

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The thing is, I'm soliciting opinions and throwing out objections as they occur to me. I've never said what research I've done, nor do I know where I'm finally going to come down. It bugs me to have those who don't know me tell me what I believe and presume they know what research I've done .. and that it's inadequate. And when the heck did I say I didn't believe failure would happen to me?

There, now I feel better. Slightly.

In your case you're combining RAID with mirroring. Which is great but that's what I mean by expense. In my case I'll need a lot more than 2TB once I get obsessed as I usually do.

I should note I'm not using RAID5 and mirroring in the same system on purpose... I just happened to have an old RAID5 array that I was already using and have it as a second source of storage for what is now my main source of AV storage... a cheap 2TB drive in my HTPC system.
The RAID5 array is the main storage for pictures and documents and such, and those are automatically copied the other direction to my HTPC as well as to my laptop (which automatically backs up to a system at work). If the house burned down I'd have to re-buy movies and music, which are replaceable, but I have off-site backup for my irreplaceable documents and pictures, all without relying on a 3rd party service.

My HTPC runs all the time to provide music to the house via iTunes (with an iPhone for remote control) and occasionally gets used to play a bluray disc if I want the better quality or haven't copied it to the hard drive so TiVo can play it. (One cool detail: I have PowerDVD set to always use SPDIF or HDMI output, and the main audio defaults to analog so iTunes can play music in the house at the same time that somebody is watching a movie )
- that really has nothing to do with your line of inquiry, I just wanted to share

__________________
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Would you mind giving a rough estimate of the cost of your raid array? I'm thinking that even if it costs less once we're talking 5,000+ movies, the initial investment for that sort of capacity is large.

That depends. If you are looking for a solution that will never cost anything to upgrade, then yes, you are looking at a very large cash outlay. Outside the enterprise environment, few people would seek such a solution, and in general even enterprise entities are going to seek scalable solutions, not solutions that are suited day one to their final task. Initially, a mid-size to large tower can be a good housing solution. This case,for example, is only $55, or $45 after the mail-in rebate. It can easily house 6 or 7 hard drives (9 if you don't have any optical drives). A pair of these can be used to create two mirrored systems, one for primary storage and the other for automated backup. My recommendation is to pick up a couple of small hard drives, maybe on Craig's list, or maybe you have a couple lying around, for the OS drives. 45G is more than plenty. With that and a couple of last-generation motherboards, you can build a couple of nice arrays expandable to 20T RAID6 with 2 parity drives for maybe $200 - $250, excluding the data drives. These should last you several years before you need to consider expansion solutions.

The sweet spot right now for hard drives seems to be the 3T drive, at just a bit over $50 per T. Four of them arranged in a pair of 3T RAID6 arrays with a drive missing or two member RAID5 arrays each is a good starting point, costing about $600 for the drives. If your recording habits are anything like mine, this should last for close to 2 years before you need to buy more drives. By that time, the 4T drives may have dropped to under $200.

First of all, I am not sure what quality of disks you are going to get for $1. Certainly I have not seen any name brand disks selling that low. You may find yourself having to replace those disks in less than 5 years, or in not much more than 5 years in any case. Since a relatively large amount of space on each BRD is going to be wasted, it will probably take in excess of 200 disks to achieve the same day 1 storage capacity as the RAID arrays. That plus the burner comes to, say, $400, vs perhaps $550 for each array. With backups, that comes to maybe $600 for BRD storage vs. $1100 for a pair of 3T arrays. Since the BRD media writes many times slower than the RAID array, you also have to consider your own time and how much it is worth.

Quote:

Originally Posted by markmarz

Net present value factors in with such a large difference in initial cost, I think. Plus the cost of blu ray per movie is paid once, not ongoing as with drive replacements, power consumption, etc.

Again, that is not true. Those BR disks will almost certainly have to be replaced within 10 years, perhaps much less. There is also an excellent chance the data on some of them will be lost for good, perhaps in as little as 4 or 5 years.

Quote:

Originally Posted by markmarz

Also I'm having trouble figuring out the $70 per spindle figure you mentioned in your other reply.

A 20 drive chassis like this one, costing $1300 comes in at $65 per drive, plus the cost of the HBA, which is around $100, or 2 HBAs at about $200 to host two 10 drive arrays in a single enclosure.

Quote:

Originally Posted by markmarz

What's the capacity per spindle?

The largest consumer grade drives of which I know at the moment are 4T. The most economical per byte are 3T. That should change in the next few months, but if you are taking the plunge now, 3T is the way to go. In a RAID 6 configuration with one OS drive and an optical drive in each tower, that gives those $45 towers an ultimate data capacity of 15T, or perhaps 2500 HD movies, before you need to consider an expansion solution like the one above. If you want to push the resiliancy a bit, you could go with RAID5 and stretch it to 18T. I don't really recommend it, but given a robust backup solution, one can skimp a bit on the drive redundancy.

Quote:

Originally Posted by markmarz

Your comment on h.264 is interesting; that's quite a savings from 10gig to 6gig per movie; I'll have to look into that.

Well, using the default conversion in VideoRedo TV Suite, it's more like 7G vs. 10G, but the point still stands. One can reduce the rate to 50%, or even lower, but one is likely to start noticing a lot of artifacts if one does.

I should note I'm not using RAID5 and mirroring in the same system on purpose... I just happened to have an old RAID5 array that I was already using and have it as a second source of storage for what is now my main source of AV storage... a cheap 2TB drive in my HTPC system.

Yeah, but he seems to be starting from scratch.

BTW, I don't choose to employ disk or array mirrroring myself. The reason is, the most common cause of data loss is human error. Most such errors are caught in fairly short order, however, so instead of mirroring, I copy all file updates once a day using rsync. I only eliminate deleted files on the backup server manually once a month or so. That way, the chances of catching and fixing the odd Oops! here and there is excellent. With mirroring, all updates and deletes are propagated to the backup immediately.

BTW, With 4 2TB drives, you could run RAID-5 and have 6GB of storage instead of just mirroring to get 4TB. It would be slower, but for the purposes of backing up and serving movies, it's fast enough.

No it wouldn't. A RAID5 array with 4 spindles should be faster than a RAID1 + 0 array with 4 spindles. Essentially, with the RAID1 + 0 array, data would be reading or writing to two drives simultaneously, while the RAID5 array will be reading or writing the same amount of data to 3 drives, with a corresponding increase in speed of nearly 50%, all else being equal.

My 8 spindle RAID6 array can read and write data in excess of 450 MB/sec, which is far, far faster than any of the individual drives can be read or written.

Quote:

Originally Posted by pmiranda

Personally I don't put all my eggs in one box anymore, though... I have one computer with a 2TB drive that holds all the movies I've bothered to store and serves them, and it automatically mirrors across the network to another computer that has a 1.5TB (usable space) RAID5 array. Both computers run pytivo and can serve up movies in the event of any one failure.

See my response above. Implementing a regular data sync, rather than mirroring represents a better example of not putting all the eggs in one basket.

Quote:

Originally Posted by pmiranda

The whole thing is way less effort than burning anything to optical media. It's so little effort that adding the step of transcoding to H.264 and possibly losing some quality just isn't worth it for me

I have never been able to discern any loss in PQ using the default options in VRD. I've looked quite closely.

Quote:

Originally Posted by pmiranda

although it might make it faster for when I want to take a something to-go on my laptop or phone.

Not just then. It's up to four times faster transferring to a THD and 3 times faster transferring to an S3. The space savings is also significant from a cost savings, both in terms of the investment in drives and the reduced power costs. Twenty drives use considerably less power than 30.

Of course I was especially glad of the decreased storage size when the flooding in Thailand caused the prices of hard drives to skyrocket. Recoding to h.264 prevented me from having to buy new drives when 3T spindles were over $350 a pop.

It's a lot for me to digest .. the only thing I'm not convinced of is your statement that the BR discs will almost certainly have to be replaced in 10 years, and so on.

How do you figure? I haven't had to replace a single dvd-r as yet, and some of them are over 10 years. Of course I haven't checked every single one of them, just a random sample driven by what I want to watch. But aren't blu rays less likely to fail than dvd-r? I'm not saying they won't fail (for anyone who wants to put words in my mouth); I'm trying to weigh the likelihood vs the cost of hard drives.

It's a lot for me to digest .. the only thing I'm not convinced of is your statement that the BR discs will almost certainly have to be replaced in 10 years, and so on.

How do you figure? I haven't had to replace a single dvd-r as yet, and some of them are over 10 years.

The Library of Congress has run extensive durability tests on digital storage media. They very widely not only from manufacturer to manufacturer but even between batches from a single manufacturer. Some DVDs faded to complete unusability in under 3 years. Others have held up well for over 10 years in the same environment. The thing is, there is no way for a consumer to tell whether the media he is using at the moment will wear well or poorly. Ten years is a very good number to reach without any data loss. Of course, the environmental conditions make a huge difference. If kept in ideally low temperatures at ideal humidity in complete darkness in an antiseptic environment, recordable media can last much, much longer than media subjected to excessively high or low humidity, high temperatures, and onslaught by mold and fungus. My brother, for example, turns off his air conditioner completely when he is away from the house, and the daily temperature regularly soars to 40C or above. My house, however, has temperature controlled rooms where the temperature never exceeds 25C. Most, but by no means all, of my digital recording media, and all of my commercially recorded discs are still intact AFAIK. None of my brother's media more than 10 years old is.

Quote:

Originally Posted by markmarz

Of course I haven't checked every single one of them, just a random sample driven by what I want to watch. But aren't blu rays less likely to fail than dvd-r?

I don't know for a fact, but I doubt it. Of course, as I mentioned, DVD-R media varies a great deal in its longevity.

Quote:

Originally Posted by markmarz

I'm trying to weigh the likelihood vs the cost of hard drives.

I'm just not sure it's a terribly meaningful comparison.

Note one thing, BTW. You had mentioned the cost of power keeping drives spinning. It is a significant cost, to be sure. One can, however, do some things to mitigate those costs. One is to shut down the array when not in use. The drives can then be allowed to spin down. Bringing the array back up only takes a few seconds. This can be especially practical for the backup. One can have the array automatically dismounted and disassembled after the daily rsync, and then fired up every day before the rsync. (Yet another advantage of not employing mirroring.)

The last time I checked, mdadm did not support the automatic spin-down of RAID members, but that was several months ago, and it may now be supported. Of course, purchasing green drives and slower drives at the outset will also help. For most residential users, the loss in performance is more than offset by the increase in performance engendered by employing an array, assuming it is an issue in the first place.

A couple last notes on my comments...
My RAID5 is dog slow since it's basically running in software. If you have a hardware controller it should indeed be faster than a single drive.
I use GoodSync to "mirror" between computers, with it setup to automatically add files in one direction and only at chosen intervals, but it won't delete anything without user intervention and it won't do the sync if more than X% of the fileset changes. If you inadvertently modify a file this won't help, but for this stuff that would almost never happen anyway. I'm sure you can get the same effect with other, free, software as well.

__________________
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- Premiere

A couple last notes on my comments...
My RAID5 is dog slow since it's basically running in software. If you have a hardware controller it should indeed be faster than a single drive.

Untrue. In years past, hardware RAID was faster than software RAID, but it has not been true now for well over half a decade. With today's multi-GHz 64 bit processors, software RAID is almost always faster than hardware RAID. What's more, true hardware RAID is pretty rare, only found in very high dollar RAID controllers. Most so-called RAID controllers and RAID motherboards run what is known as "fake RAID", which is actually software RAID embedded on the controller and implemented through the BIOS.

If you are having problems with speed, unless you are running an ancient 386 or something, it isn't due to the slowness of software RAID. I am running md RAID under Debian "Squeeze" Linux on two fairly old AMD Athlon 64 x 2 processors, each with a little $45 four port HBA, and as I mentioned, the systems are easily capable of reading and writing in excess of 450 MBps.

What is true is the RAID implementation is limited by the speed of the expansion interface. If your drive controller is a simple PCI card, it will be limited by the 133 MBps bandwidth of the PCI bus. PCI-x or better yet PCI-E adapters are preferred, since both are much faster. PCI-E interfaces can support up to 8GBps in both directions. Of course older drives with slower interfaces, slower spin rates, and smaller caches will also perform more poorly than more modern, higher speed drives.

Multi-lane RAID implementations are also much faster than Port Multiplier implementations, but also much more costly, and usually not able to support as many spindles overall. PM implementations are more than sufficient for most home users, though. I did run a multi-lane system for a while, but currently I am using Port Multipliers.

Quote:

Originally Posted by pmiranda

I'm sure you can get the same effect with other, free, software as well.

This has been a great discussion, I appreciate everyone's input immensely!

I'm now leaning more towards the hard drive array solution, provided I can find a green solution and keep the initial investment low. I like the idea of having the drives spin down etc; in fact I see no need to keep the system up at all (especially backup) until needed. I'm not even sure I need to run raid .. but all this is better handled in another thread. There's probably lots already on the subject so I'll browse around and if I have something not handled in an existing thread, I'll open a new one.

Some of this has to come down to your preferred viewing experience too.

I think that for many people here a viewing experience in which you have to first decide what you want to watch, run upstairs, find the disc, and play it from a single location, is extremely nonoptimal.

People like to be able to have all of their movies remotely browsable and watchable, which you can't do with 2700 blu-ray discs.

AVSforum used to have a sticky in its HTPC subforums for media servers. That might be a good place to look.

Quote:

Originally Posted by markmarz

This has been a great discussion, I appreciate everyone's input immensely!

I'm now leaning more towards the hard drive array solution, provided I can find a green solution and keep the initial investment low. I like the idea of having the drives spin down etc; in fact I see no need to keep the system up at all (especially backup) until needed. I'm not even sure I need to run raid .. but all this is better handled in another thread. There's probably lots already on the subject so I'll browse around and if I have something not handled in an existing thread, I'll open a new one.